A recent -- and overall sensible -- New York Times editorial by the SETI Institute's Seth Shostak makes me wonder if a long-overdue paradigm shift is finally underway among American SETI scientists.
For a long time, as I've written about here many times before, American SETI scientists -- with Shostak predominant among them -- have dismissed out of hand the possibility that an advanced extraterrestrial civilization has ever ventured to travel to our solar system. Unexplained phenomena such as UFO reports cannot be evidence of extraterrestrial visitation, the reasoning goes, because interstellar travel is simply prohibitively expensive regardless of a civilization's age or technological level of development. Rather than looking for signs of visitation, they insist, we should limit our search for E.T. to looking for radio and perhaps laser transmissions.
In his recent column, Shostak doesn't back off that stance explicitly. His column discusses what he views as the apparent futility of human interstellar travel, given our current and projected states of knowledge and technological development. (I'm going to set aside his main thesis, which many have questioned, including myself.)
What intrigues me is Shostak's suggestion that what may be within our technological grasp are small, smart interstellar probes that remotely explore extrasolar planetary systems and then radio the results back to Earth. While such missions may require many decades before we get the results from distant probes sent on long journeys light-years from Earth, such probes are conceivable given our current technological development.
What is intriguing about Shostak's suggestion, of course, are its as-yet unstated implications.
The SETI radio searches are based on the hypothesis that since we -- an intelligent, technological civilization -- use radio to communicate, so would an advanced technological civilization located in an extrasolar planetary system. We search for extraterrestrial radio and laser signals because we know we, as a technological civilization, are capable of sending them.
On the other hand, if we are capable of sending unmanned probes to other planetary systems light-years from our own and to wait patiently for the results, then perhaps an intelligent species elsewhere has done the same, and the evidence is hiding somewhere in our own solar system, waiting for us to discover it.
Should SETI radio searches be complemented by a systematic search for evidence of extraterrestrial artifacts in our neighborhood?
Of course they should.
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